Recirculating linear gas drive system

• US 6,694,858 B2
• Filed: 08/29/2002
• Issued: 02/24/2004
• Est. Priority Date: 08/29/2001
• Status: Active Grant

• Current Assignee: LEWA GmbH (Atlas Copco AB), CDK Services Limited
• Original Assignee: CDK Services Limited
• Inventors: Grimes, Edward C.
• Primary Examiner(s): Lazo, Thomas E.
• Application Number:
  US10/231,928
• Publication Number:
  US 20030121405A1
• Time in Patent Office: 544 Days
• Field of Search: 604/12, 603/72, 912/47, 913/17, 913/50, 912/99, 166/68.5, 166/75.11
• US Class Current: 91/299
• CPC Class Codes: F01L 31/00 Valve drive, valve adjustment during operation, or other valve control, not provided for in groups F01L15/00 - F01L29/00 sensing elements measuring the variable or condition to be controlled or regulated F01B25/04
• CPC Class Codes: F04B 47/04 the driving means incorporating fluid means
• CPC Class Codes: F04B 9/125 reciprocating movement of the pumping member being obtained by a double-acting elastic-fluid motor

Abstract

A system to provide mechanical energy to well-head equipment by directing pressurized gas existing in nearby pipelines to an engine. The engine is a linearly reciprocating piston in a closed cylinder driven by pressure differentials between the gas on either side of its piston, the differential being controlled by a switching valve which directs higher and lower pressured gas to the appropriate side of the piston, and which recirculates spent gas from the lower pressure side of the piston back to the pipeline. The system is a closed system, and avoids venting or flaring gas used in the engine.

Claims

1. A system comprising:

produced gas

a pipeline with gas at a lower pressure

a manifold with flow control valve

a reciprocating power unit

a drive connection from power unit to a powered unit

a flow-directing switching means which, in time with the drive'"'"'s reciprocating movement to the end-point positions, switches communication of produced gas and pipeline with the appropriate sides of the power unit.

2. A system as in claim 1 where the flow-directing switching means comprises:

two opposed pistons tightly fitted and moveable in a linear fashion within closed cylinders

each opposed piston connected to the other via a body between them which is itself tightly fitted and slideable within a fourth cylinder fixed to both of said opposed piston'"'"'s cylinders

said body having cavities which match with and form different conduits between five ports in said fourth cylinder at different orientations of said body within said fourth cylinder'"'"'s wall, each port communicating with said manifold

two flow control valves deployed in the manifold, each control valve to control the rate of gas flow between one side of the power unit'"'"'s piston and one side of the matching one of said opposed pistons versus the other side of said opposed piston, to control the speed of reciprocation of said opposed pistons and said body.

3. A system as in claim 2 where:

when said opposed pistons are substantially at one extreme of their linear travel within their respective cylinders, said cavities and manifold form the following communications paths;

produced gas to the first side of said power unit piston and directly to one side of a matching one of said opposing pistons, and through flow-control valve to the other side of said one opposing piston

the other side of said power unit piston and directly to one side of the matching second of said opposing pistons and, through the second flow-control valve from the other side of said second opposing piston, to pipeline

such that the power unit piston is pushed in a direction from the produced gas side toward the pipeline side of its cylinder, providing power through its connecting rod to the powered unit, and such that;

the opposing piston communicating with pipeline is moved from its directly communicating side toward its flow-control communicating side and spent gas from the power unit'"'"'s piston then flows to pipeline

essentially simultaneously, the other opposing piston which is communication with produced gas is pushed from its directly communicating side toward its flow-control communicating side which until then had contained gas at lower pipeline pressures, and

said body is moved toward one direction in relation to said ports to alter in a timed way the conduits thus formed within the manifold and ported cylinder and body so that at the other extreme of their linear travel within their respective cylinders is caused the communications paths as follows;

produced gas to the second side of said power unit piston and directly to one side of the matching second opposing piston and through the second flow-control valve to the other side of the second opposing piston

the first side of said power unit piston and directly to one side of the matching first opposing piston and through the first flow-control valve to the other side of the first opposing piston, and to pipeline

such that the power unit piston then is pushed in the other direction, providing repeatable reciprocating linear powered motion of said drive connection, and said reversed gas-flows provide realignment of said switching valve'"'"'s internal body'"'"'s cavities with said ports to cause the further repeated redirection of gas through the manifold.

4. The system described in claim 3 where the first and second flow-control valves may be independently adjusted to vary the timing of the reciprocation, each such valve controlling the rate of gas flow required to reach equilibrium between a produced gas side and a pipeline side of the power unit'"'"'s piston for a different direction of said reciprocation.

5. The system of claim 1 which provides for the recirculation of spent-pressure exhaust gas under sufficient pressure to pipeline while providing reciprocating powered motion to an external powered device.

6. The system of claim 1 where the produced gas under pressure is from available sources at or near a natural gas producing well-head or battery, and may be well-head gas or other process gas under pressure where the pipeline with gas at lower pressure is likewise to a variety of destinations at or near the well-head or battery and may be to production pipeline or to any pipeline or destination carrying process gas which is at such lower pressure.

7. The system in claim 1 where the reciprocating power unit is either piston-driven or diaphragm driven by controlled gas pressure differential.